U.S. patent number 8,518,479 [Application Number 11/867,879] was granted by the patent office on 2013-08-27 for fabrication of fluidic features within a plastic substrate.
This patent grant is currently assigned to Affymetrix, Inc.. The grantee listed for this patent is Chuan Gao, Tianyue Yu. Invention is credited to Chuan Gao, Tianyue Yu.
United States Patent |
8,518,479 |
Gao , et al. |
August 27, 2013 |
Fabrication of fluidic features within a plastic substrate
Abstract
In one aspect of the invention, methods, and devices are
provided for creating microfluidic and nanofluidic features. In
some embodiments, such methods and devices are used to create at
least one channel of a desired volume within a channel in a plastic
substrate.
Inventors: |
Gao; Chuan (Sunnyvale, CA),
Yu; Tianyue (San Jose, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Gao; Chuan
Yu; Tianyue |
Sunnyvale
San Jose |
CA
CA |
US
US |
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Assignee: |
Affymetrix, Inc. (Santa Clara,
CA)
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Family
ID: |
47597478 |
Appl.
No.: |
11/867,879 |
Filed: |
October 5, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20130029273 A1 |
Jan 31, 2013 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60851797 |
Oct 12, 2006 |
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Current U.S.
Class: |
427/235; 427/271;
118/643; 427/256; 427/508; 118/642; 427/230; 118/641 |
Current CPC
Class: |
B81C
1/00071 (20130101); B01L 3/502707 (20130101); B01L
2200/0636 (20130101); B01L 2200/12 (20130101); B01L
2300/0867 (20130101); B81B 2201/058 (20130101); B01L
2300/0816 (20130101) |
Current International
Class: |
B05D
1/34 (20060101); B05B 12/00 (20060101) |
Field of
Search: |
;427/256,230,235,508
;118/641,642,643 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Kenis et al., Fabrication inside Microchannels Using Fluid Flow,
Accounts of Chemical Research, (2000). cited by examiner .
Oosterbroek et al., Lab-on-a-Chip, Elsevier, (2003). cited by
examiner .
Paul J.A. Kenis et al, "Microfabrication Inside Capillaries Using
Multiphase Laminar Flow Patterning," Science 285, 83 (1999). cited
by applicant.
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Primary Examiner: Empie; Nathan
Assistant Examiner: Jiang; Lisha
Attorney, Agent or Firm: Affymetrix, Inc.
Parent Case Text
RELATED APPLICATIONS
The present application claims priority from U.S. Provisional
Patent Application Ser. No. 60/851,797, filed Oct. 12, 2006 and is
hereby incorporated by reference herein in its entirety for all
purposes.
Claims
What is claimed is:
1. A method for constructing at least one channel within a
preexisting channel of a substrate, the method comprising:
providing a substrate, wherein the substrate comprises a
preexisting channel; introducing a first fluid and a second fluid
into the preexisting channel through a plurality of introductory
channels, wherein introducing the first and second fluids comprises
attaching a control element to the substrate, wherein the control
element comprises the plurality of introductory channels, and
wherein the first and second fluids are immiscible; curing the
first fluid, wherein curing the first fluid does not cure the
second fluid; removing the uncured second fluid from the substrate,
thereby constructing at least one constructed channel within the
preexisting channel; and repeating the introducing, curing, and
removing steps, thereby constructing at least one additional
channel within the at least one constructed channel.
2. The method of claim 1, wherein introducing the first and second
fluids is repeated at least once to create an alternating pattern
of the first and second fluids within the preexisting channel.
3. The method of claim 1, wherein the first and second fluids are
introduced into the preexisting channel in parallel.
4. The method of claim 1, wherein introducing the first and second
fluids is performed with at least two different sets of
introductory channels.
5. The method of claim 1, wherein the at least one constructed
channel comprises a channel width, wherein the first fluid is
introduced at a different flow rate than the second fluid, and
wherein the channel width is based upon, at least in part, the
difference in the flow rate for the first and second fluids.
6. The method of claim 5, wherein the channel width ranges from 100
nanometers to 10 microns.
7. The method of claim 6, wherein the channel width ranges from 200
nanometers to 1 micron.
8. The method of claim 7, wherein the channel width is 500
nanometers.
9. The method of claim 1, wherein the first fluid is curable with
ultraviolet radiation, wherein the second fluid is not curable with
ultraviolet radiation, and wherein curing the first fluid comprises
exposing the first and second fluids within the preexisting channel
to ultraviolet radiation.
10. The method of claim 1, wherein the substrate comprises a
plastic material.
11. The method of claim 10, wherein the plastic material is
selected from the group consisting of polycarbonate, polymethyl
methacrylate, and polydimethylsiloxane.
12. The method of claim 1, wherein the at least one constructed
channel comprises a shape selected from the group consisting of
straight, curved, L shape, V shape, funnel, and zigzag.
Description
BACKGROUND OF THE INVENTION
The present invention relates to the field of micro and
nanofluidices. For example, the methods and devices of the present
invention can be used to manufacture microfluidic features,
specifically in manufacturing microchannels and nanochannels in
plastic substrates.
Interest has been growing in the fabrication of microfluidic
devices. Typically, advances in the semiconductor manufacturing
arts have been translated to the fabrication of micromechanical
structures, e.g., micropumps, microvalves and the like, and
microfluidic devices including miniature chambers and flow
passages.
There are several techniques that have been developed to fabricate
microfluidic channels on materials such as, for example, silicon,
glass, quartz, polymeric films, silicon carbide and thermoplastic.
Techniques such as, for example, chemical wet etch, chemical etch,
laser cutting, laminate laser cutting, micromolding,
photopolymerization, hot embossing and injection molding are
current methods of fabricating fluidic features, however, have
feature size limitations, cost issues and may not be appropriate to
be used on plastic materials when fabricating features, such as
channels, at the smaller size ranges described in this application.
In order to fabricate nanochannels, for example, the semiconductor
industry has utilized the conventional electron-beam lithography
process which is relatively expensive and inherently slow. There is
a need to develop a simple method to manufacture microchannels at
the lower scale and nanochannels on plastic substrates at a lower
cost and at a higher throughput.
BRIEF SUMMARY OF THE INVENTION
An embodiment of the present invention provides methods and devices
for constructing at least one channel of a desired volume in a
plastic substrate. At least one fluid that is curable is introduced
into the channel in the substrate by a dispensing mechanism. The
channel of a desired volume to be created comprises a width which
is varied to provide a desired volume. A curing mechanism cures at
least one fluid such that an alternating pattern of the cured
material creates at least one channel of a desired volume within
the channel in a substrate.
According to a another embodiment of the present invention, the
methods and devices further include a second fluid, wherein the
second fluid is immiscible with the first fluid. In one preferred
aspect of the invention, the width is in the range of 100
nanometers to 10 microns. In a more preferred embodiment of the
present invention, the width is in the range of 200 nanometers to 1
micron. In a most preferred embodiment of the present invention,
the width is approximately 500 nanometers. According to another
aspect of the present invention, the first fluid, which is curable,
is a UV epoxy material which is cured by a UV curing mechanism
while the second fluid is water.
According to an alternate embodiment of the present invention, the
channel of a desired volume to be created is an open microchannel.
In one aspect of the present invention, the methods and devices
further comprise a mask during the curing process to provide an
alternating pattern of the cured material. In one preferred aspect
of the invention, the width is in the range of 1 micron to 50
microns. In a more preferred embodiment of the present invention,
the width is in the range of 5 microns to 20 microns. In a most
preferred embodiment of the present invention, the width is
approximately 10 microns. In a preferred embodiment, SU-8 is used
to create at least one microchannel of a desired volume.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and form a
part of this specification, illustrate embodiments of the invention
and, together with the description, serve to explain the principles
of the invention:
FIG. 1 illustrates an outline showing the steps to construct at
least one channel of a desired volume within a channel in a
substrate according to an embodiment of the present invention.
FIGS. 2a-2e illustrate examples of constructed channels of a
desired volume(s) according to some embodiments of the present
invention. FIG. 2a is an image of a channel of a desired volume
formed within a channel in a substrate. FIG. 2b illustrates a
constructed curved channel of a desired volume. FIG. 2c illustrates
multiple channels of a desired volume(s) constructed within a
channel in a substrate. FIG. 2d illustrates multiple constructed
zigzag types of channels of a desired volume(s). FIG. 2e
illustrates a constructed channel of a desired volume within a
channel that comprises a well in a substrate.
FIG. 3 illustrates an outline showing the steps to construct at
least one channel of a desired volume within a channel in a
substrate comprising at least 2 fluids according to another
embodiment of the present invention.
FIGS. 4a-4c illustrate examples of mechanisms to provide
introductory channels that supply material into a channel in a
substrate according to an embodiment of the present invention. FIG.
4a illustrates a substrate that comprises both the channel in which
the channel of a desired volume will be constructed and the
introductory channels. FIG. 4b illustrates a control element that
comprises the introductory channels. FIG. 4c illustrates a channel
in a substrate wherein the channel of a desired volume will be
constructed.
FIGS. 5a-5d illustrate an example of how multiple control elements
are used to construct multiple channels of desired volume(s)
according to an embodiment of the present invention. FIG. 5a
illustrates a channel in a substrate wherein three channels of a
desired volume(s) will be constructed using three control elements.
FIGS. 5b, 5c, and 5d illustrate the control elements where the
introductory channels are provided. The control element as shown in
FIG. 5b is attached to the side surface, the control element as
shown in FIG. 5c is attached to the top surface and the control
element as shown in FIG. 5d is attached to the bottom surface of
the substrate with the channel wherein the multiple channels of a
desired volume(s) will be created.
FIG. 6 illustrates an outline showing the steps to construct at
least one open microchannel of a desired volume within an open
channel in a substrate according to an embodiment of the present
invention.
FIGS. 7a-7d illustrate some of the steps involved in creating open
microchannels of a desired volume(s) by using a mask and exposure
step according to an embodiment of the present invention. FIG. 7a
illustrates an example of an open microchannel in a substrate. FIG.
7b illustrates a microchannel filled with a curable material. FIG.
7c illustrates an example of an exposure step. FIG. 7d illustrates
the constructed open microchannels of a desired volume(s).
FIG. 8 illustrates a substrate with constructed open microchannels
of a desired volume according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
I. General Description
The present invention cites certain patents, applications and other
references. When a patent, application, or other reference is cited
or repeated below, it should be understood that it is incorporated
by reference in its entirety for all purposes as well as for the
proposition that is recited.
As used in this application, the singular form "a," "an," and "the"
include plural references unless the context clearly dictates
otherwise.
Throughout this disclosure, various aspects of this invention can
be presented in a range format. It should be understood that the
description in range format is merely for convenience and brevity
and should not be construed as an inflexible limitation on the
scope of the invention. Accordingly, the description of a range
should be considered to have specifically disclosed all the
possible sub-ranges as well as individual numerical values within
that range. For example, description of a range such as from 1 to 6
should be considered to have specifically disclosed sub ranges such
as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6,
from 3 to 6 etc., as well as individual numbers within that range,
for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the
breadth of the range.
II. Specific Embodiments
According to an embodiment of the present invention, methods and
devices for constructing at least one channel of a desired volume
in a plastic substrate are provided. At least one fluid that is
curable is introduced into a channel in the substrate by a
dispensing mechanism. The channel of a desired volume to be created
comprises a width and the width is varied to provide a desired
volume. A curing mechanism cures at least one fluid such that an
alternating pattern of the cured material creates at least one
channel of a desired volume within the channel in the
substrate.
According to one aspect of the present invention, the steps of
constructing at least one channel of a desired volume within a
channel in a substrate is outlined in FIG. 1. The substrate (101)
with a channel (102) is provided (100). At least one fluid that is
curable is dispensed into the channel in the substrate (103). A
curing process is performed (104) such that an alternating pattern
of the cured material creates at least one channel of a desired
volume within the channel in the substrate. Once the material is
cured, any excess material (for example, non-curable material) can
be removed (105). A channel of a desired volume is constructed
within a channel in a substrate (106).
According to another embodiment of the present invention, the
volume(s) of the channel(s) to be constructed can be controlled. In
one aspect of the present invention, the channel to be constructed
further comprises a width. In a preferred embodiment, the volume of
the channel can be controlled by adjusting the width of the channel
to be created. There are several parameters that can change the
width, for example, flow rate, pressure, temperature, material
properties (for example, viscosity).
The channels which can be modified to construct the channels with a
desired volume(s) can be in various substrates, which are
understood by one skill in the art in various applications, for
example, biological, biotechnology, chemical reactions, and the
like. Although indicative of a rectangular shape, it will be
readily appreciated that the substrate may be embodied in any
number of shapes depending upon the particular need. Additionally,
these dimensions will typically vary depending upon the number of
operations to be performed by the substrate, the complexity of
these operations and the like. In general, the substrate is
fabricated using one or more of a variety of methods and materials
suitable for micro fabrication techniques such as embossing,
injection molding, thermal bonding thermal forming, etc. Typical
plastic materials used for microfluidics are thermal-plastics:
polycarbonate, polymethyl methacrylate (PMMA), COC, etc. and
elastomers: polydimethylsiloxane (PDMS). For example, in a
preferred embodiment, the body of the device may be injected molded
parts from Polycarbonate. According to one embodiment of the
present invention, the channel can be in a substrate, for example a
microfluidic device such as a lab card (see copending patent
application Ser. No. 11/867,909, which is incorporated by reference
in its entirety for all purposes).
According to another embodiment of the present invention, the
configuration of a channel(s) of a desired volume to be constructed
can depend on several factors, for example, curing mechanism, the
number of fluids, the fluid properties, the pressure, the flow
rate, the dispensing mechanism, etc. According to an embodiment of
the present invention, various configurations of the channels of a
desired volumes can be created. Examples of the various
configurations of the constructed channels of a desired volumes
(106) within a channel (102) in a substrate (101) are illustrated
in FIGS. 2a-2e according to some embodiments of the present
invention. These diagrams are merely examples, which should not
unduly limit the scope of the claims. One of ordinary skill in the
art would recognize many variations, alternatives, and
modifications. For example, in this application, the substrate
(101) represented in the drawings can also include other features,
such as other microfluidic features according to another embodiment
of the present invention. A fluid that is curable (103) is
dispensed into the channel (102) and cured to construct a channel
of a desired volume (106) according to an embodiment of the present
invention. FIG. 2a is an image of a channel of a desired volume
(106) created within a straight channel (102) in a substrate (101).
FIG. 2b illustrates a constructed curved channel of a desired
volume (106). Other examples include, L shape channels, V shape
channels, funnel type channel, etc. According to another embodiment
of the present invention, the method includes a plurality of
fluids, for example, a first fluid (103) and a second fluid (106)
that flow through the channel in an alternating pattern as shown in
FIGS. 2c and 2d. FIG. 2c illustrates multiple constructed channels
of a desired volume(s) (106) from within a straight channel (102)
in a substrate (101). FIG. 2d illustrates multiple constructed
zigzag type channels of a desired volume(s) (106). The channels of
a desired volume(s) can be of a different volume from each other
according to an embodiment of the present invention. Another
example of a variation of the configuration of a channel is
illustrated in FIG. 2e. In this case, based on volume requirement
and space limitations, a channel of a desired volume is created
within a well and a channel. There can be other situations where
there might be other complicated and or undesired features such as
abrupt features, rough areas, divots, and the like in an area of a
substrate that can also be overcome by using the method described
above according to another embodiment of the present invention.
Examples of abrupt angles (110) are shown in FIG. 2d and FIG.
2e.
The number of channels of a desired volume(s) to be constructed
will depend on several factors such as, for example, the size of
the channel in the substrate, the shape of the channel, the fluid
properties and the like. In general, the channel in the substrate
will typically range from about 20 to about 1000 microns wide,
preferably, 100 to 500 microns wide and about 5 to 100 microns
deep. Although described in terms of channel, it will be
appreciated that these chambers may perform a number of varied
functions, e.g., as storage chambers, incubation chambers, mixing
chambers and the like.
According to one aspect of the present invention, the steps of
another method of constructing at least one channel of a desired
volume (106) within a channel in a substrate is outlined in FIG. 3.
The substrate (101) with the channel (102) is provided (100), at
least two materials where at least one material is curable and
other not curable are dispensed into the channel in the substrate
(301) in an alternating pattern by a dispensing mechanism. The
first fluid is curable and the second fluid is immiscible with the
first fluid. The channel is filled with the fluids in an
alternating pattern such that they form distinct fluid streams. The
parallel laminar flow properties will keep the immiscible fluids
separated and dictate the shape of the channels of a desired
volume(s) to be created. A curing mechanism cures the first fluid
(104), while the fluids are in the channel. Once the first fluid is
cured, the second fluid can be removed (105). In performing these
process steps, at least one channel of a desired volume is
constructed within the channel in the substrate (106). Depending on
several factors such as, for example, the curing mechanism,
material, application, the dimensions of the channel, the
dimensions of a desired constructed channel, the fluids can be
static or moving during the curing process according to an
embodiment of the present invention.
According to another embodiment of the present invention, the
volume(s) of the channel(s) to be constructed can be controlled. In
one aspect of the present invention, the channel to be constructed
further comprises a width. In a preferred embodiment, the volume of
the channel can be controlled by adjusting the width of the channel
to be created. There are several parameters that can change the
width, for example, flowrate, pressure, temperature, material (for
example, viscosity). In a preferred embodiment, the flow rate is
adjusted by varying the pressure. For example, the width of the
channel (106) as shown in FIG. 2a can be increased by decreasing
the flow rate of the curable material (103) and/or increasing the
flow rate of the non curable material that flows through the
channel (102) to be created. The volume is changed as a result of
the adjustment of the width of the channel. In a preferred
embodiment, the volume of the channel is controlled by adjusting
the width of the channel to be created. In a preferred embodiment
of the present invention, the width is in the range of 100
nanometers to 10 microns. In a more preferred embodiment of the
present invention, the width is in the range of 200 nanometers to 1
micron. In a most preferred embodiment of the present invention,
the width is approximately 500 nanometers.
According to an embodiment of the present invention, the apparatus
and method for constructing at least one channel of a desired
volume within a channel in a substrate is used to provide a channel
that has smooth surfaces (for example, no cracks, crevices,
wrinkles, bulges, etc.). The smoothness of the channel to be
constructed depends on several factors, for example, the
fabrication materials. In a preferred embodiment, the material
comprises of at least one fluid that is curable and a second fluid
that is immiscible with the first fluid. According to another
embodiment of the present invention, the curing mechanism can be
for example, UV curing, heat, time, chemistry, radiation, and
oxidation. Examples of UV curable materials include epoxy acrylate,
urethane acrylate, polyester acrylate, acrylated acrylic or other
oligomers. In a preferred embodiment of the present invention, the
curable material is preferred to have minimal or low shrinkage, for
example, Hyperbranched Polyester Acrylate formulations (see
reference, Jeffrey A. Klang and James S. Balcerski, "UV Curable Ink
Jet Raw Material Challenges", Sartomer, September 2002, page
5054-5058) which is incorporated by reference in its entirety for
all purposes. Another criterion regarding the fluid materials is
that both fluids should be compatible with the process or assay.
Examples of a second fluid include non-UV sensitive material,
water, organic solvents, alcohols, etc. One of ordinary skill in
the art would recognize many variations, alternatives, and
modifications. Alternately, a surface coating can be applied to
make the material compatible with the process or assay according to
another embodiment of the present invention.
According to another embodiment of the present invention, the
fluids are dispensed into the channel at the same time, adjusting
the flow rates of the fluids to determine the width of the channel
to be constructed as mentioned previously. The fluids flow in
parallel through the channel. According to another aspect of the
present invention, introductory channels that introduce fluids into
the channel in the substrate are provided. Examples of methods to
provide the introductory channels are shown in FIGS. 4a-4c
according to an embodiment of the present invention. These diagrams
are merely examples, which should not unduly limit the scope of the
claims. One of ordinary skill in the art would recognize many
variations, alternatives, and modifications. In one example as
shown in FIG. 4a, the substrate (101) includes both the channel
(102) in which the channel of a desired volume will be constructed
and the introductory channels (401) to facilitate the dispensing of
the fluids into the channel (102). Dispensing mechanisms are well
known to one skilled in the art, for example, syringe pumps and the
use of air pressure. The dispensing mechanisms may include a
plurality of valves and air pressure that control the fluid flow of
the liquids into the specific channels. Computer software products
are provided to control various active components (for example,
valves to control the liquid), temperature and measurement devices
according to another embodiment of the present invention. The
system may be conveniently controlled by any programmable device,
preferably a digital computer such as a Dell personal computer. The
computers typically have one or more central processing unit
coupled with a memory. A display device such as a monitor is
attached for displaying data and programming. A printer may also be
attached. A computer readable medium such as a hard drive or a CD
ROM can be attached. Program instructions for controlling the
liquid handling may be stored on these devices.
According to an alternative embodiment of the present invention,
the control element (400) is a separate substrate from the
substrate that has the channel in which the channel of a desired
volume will be constructed in, for example, as shown in FIG. 4b.
The control element (400) can be attached to the substrate with the
channel wherein the channel of a desired volume is going to be
constructed as shown in FIG. 4c. The introductory channels can be
of various configurations (for example, conical, straight, curved,
angled, etc.). According to an embodiment of the present invention,
the substrate with the channel wherein the channel of a desired
volume is going to be created is typically part of a substrate that
comprises other microfluidic features, for example, other channels,
storage areas, and the like. The drawings of the channels and
control elements are simplified in this specification for
demonstration purposes. These diagrams are merely examples, which
should not unduly limit the scope of the claims. One of ordinary
skill in the art would recognize many variations, alternatives, and
modifications. The design of a control element can be dependent on
the configuration of the substrate with the channel wherein the
channel of a desired volume is going to be created. In a preferred
embodiment, the control element are temporarily attached to assist
in creating the channel(s) of a desired volume(s). Attaching
mechanisms are well known in the art for someone skilled in the
art, for example, clamping, use of gaskets, and the like.
According to another embodiment of the present invention, a
plurality of channels of desired volumes can be created within a
channel in a substrate by using a control element (400) multiple
times. For example, in creating the three channels of a desired
volumes shown in FIG. 5a, a control element (400) similar to the
one shown in FIG. 4b can be used to create the first channel by
having a non-curable fluid take up the space where additional
channels are to be created later according to another embodiment of
the present invention. Once the first channel is cured and created,
then the same control element may be used again to create
additional channels within the same channel in the substrate.
According to an embodiment of the present invention, a dispensing
mechanism dispenses a plurality of fluids in an alternating pattern
into a channel in a substrate to create multiple channels of a
desired volume. FIGS. 5a - 5d illustrate an example of a plurality
of control elements (400) for constructing multiple channels of a
desired volume according to an embodiment of the present invention.
These diagrams are merely examples, which should not unduly limit
the scope of the claims. One of ordinary skill in the art would
recognize many variations, alternatives, and modifications. FIG. 5a
illustrates a substrate wherein three channels of a desired volume
will be constructed using control elements (FIGS. 5b, 5c, and 5d)
that will provide the introductory channels. The control element as
shown in FIG. 5b is attached to the side surface, the control
element as shown in FIG. 5c is attached to the top surface and the
control element as shown in FIG. 5d is attached to the bottom
surface of the substrate with the channel wherein the multiple
channels will be created (FIG. 5a). The control element (400) as
shown in FIG. 5b provides two introductory channels (401b and 401f)
that introduces non-curable fluids into two corresponding channels
(106b and 106f) in the main substrate (FIG. 5a). The control
element (400) as shown in FIG. 5c provides four introductory
channels (401a, 401c, 401e and 401g) that introduces curable fluids
into four correspond-ing channels (103a, 103c, 103e and 103g) in
the main substrate (FIG.5a). The control element (400) as shown in
FIG. 5d provides an introductory channel (401d) that introduces a
non-curable fluid into the center channel (106d) in the main
substrate (FIG. 5a). In a preferred embodiment of the present
invention, all the fluids are introduced at the same time. Once the
proper flow of the fluids are formed, the curing process is applied
forming the three channels as indicated in FIG. 5a. According to
another embodiment of the present invention, the introductory
channel that is in the same substrate as the channel of a desired
volume is being created is filled with curable material and cured.
The mechanisms and concept describe above can also be applied when
creating additional multiple channels of a desired volume(s). One
of ordinary skill in the art would recognize many variations,
alternatives, and modifications.
According to an embodiment of the present invention, an apparatus
and method for constructing at least one open microchannel within
an open channel in a substrate using a mask are provided. At least
one channel with a desired volume in the substrate is constructed.
In one aspect of the present invention, the channel to be
constructed further comprises a width. In a preferred embodiment,
the volume of the channel is controlled by adjusting the width of
the channel to be created. In one preferred aspect of the
invention, the width is in the range of 1 micron to 50 microns. In
a more preferred embodiment of the present invention, the width is
in the range of 5 microns to 20 microns. In a most preferred
embodiment of the present invention, the width is approximately 10
microns.
According to one aspect of the present invention, the steps of
constructing at least one open microchannel within an open channel
in a substrate using a mask is outlined in FIG. 6. The substrate
(101) with the open channel (602) is provided (600) and at least
one material that is curable is applied to the open channel in the
substrate (603). An example of an open channel (602) in a substrate
(101) is illustrated in FIG. 7a. The fluid can be, for example,
SU-8, photosensitive epoxies, etc. The material can be applied
directly into the open channel (602) with a dispensing mechanism,
such as those that are well known in the art for someone skilled in
the art, for example, spin coating, dip coating, various types of
pumps, and gel dispensers. These may be used to dispense a material
into the open channel with minimal concerns regarding under and
over filling. FIG. 7b illustrates an example of a curable material
(603) that is dispensed into an open channel (602) in a substrate
(101). The material is baked (604) and then goes through an
exposure step. An example of the exposure step in constructing
multiple open microchannels according to an embodiment of the
present invention, is illustrated in FIG. 7c. Specified areas of
the applied fluid material (603) are masked (605) and then exposed
to UV light (606). A mask (605) that comprises open (610) and
closed areas (611) can be placed over the material such that the
desired areas of the material to be cured are exposed (612) when
subjected to a UV light (606). Methods and apparatus for carrying
out basic photolithographic process has been described in Kovacs,
Gregory, "Micromachine Transducers Sourcebook," McGrawHill, pp
20-21, 1998, which is incorporated by reference in its entirety for
all purposes. Once the material (603) is developed (607), the
uncured material is removed (608). At least one open microchannel
of a desired volume (610) within the open channel (602) in the
substrate (101) is constructed (609) as shown in FIG. 7d. It is to
be understood that the above description is intended to be
illustrative and not restrictive. FIGS. 7a-7d are merely examples,
which should not unduly limit the scope of the claims. Many
variations of the invention will be apparent to those of skill in
the art upon reviewing the above description and figures.
According to an embodiment of the present invention, an apparatus
for constructing at least one channel of a desired volume in a
plastic substrate is provided. At least one fluid that is curable
is introduced into a channel in the substrate by a dispensing
mechanism. The first fluid flows into the channel in the substrate.
A curing mechanism cures at least the first fluid while the fluid
is in the channel to create an alternating pattern of the cured
fluid to construct at least one channel of a desired volume. The
constructed channel comprises of a width which is varied to provide
the channel of a desired volume in the substrate.
According to a another embodiment of the present invention, the
apparatus further includes a second fluid, wherein the second fluid
is immiscible with the first fluid. In one preferred aspect of the
invention, the width is in the range of 100 nanometers to 10
microns. In a more preferred embodiment of the present invention,
the width is in the range of 200 nanometers to 1 micron. In a most
preferred embodiment of the present invention, the width is
approximately 500 nanometers. According to another aspect of the
present invention, the first fluid, which is curable, is a UV epoxy
material which is cured by a UV curing mechanism while the second
fluid is water.
According to an alternate embodiment of the present invention, the
channel of a desired volume to be created is an open microchannel.
In one aspect of the present invention, the apparatus further
comprises a mask during the curing process to provide the
alternating pattern of the cured material. In one preferred aspect
of the invention, the width is in the range of 1 micron to 50
microns. In a more preferred embodiment of the present invention,
the width is in the range of 5 microns to 20 microns. In a most
preferred embodiment of the present invention, the width is
approximately 10 microns. In a preferred embodiment, SU-8 is used
to create the cured walls of the microchannels.
According to an embodiment of the present invention, a method for
constructing at least one channel of a desired volume in a plastic
substrate is provided. At least one fluid that is curable is
introduced into a channel in the substrate by a dispensing
mechanism. The first fluid flows into the channel in the substrate.
A curing mechanism cures at least the first fluid while the fluid
is in the channel to create an alternating pattern of the cured
fluid to construct at least one channel of a desired volume. The
constructed channel comprises of a width which is varied to provide
the channel of a desired volume in the substrate.
According to a another embodiment of the present invention, the
method further includes a second fluid, wherein the second fluid is
immiscible with the first fluid. In one preferred aspect of the
invention, the width is in the range of 100 nanometers to 10
microns. In a more preferred embodiment of the present invention,
the width is in the range of 200 nanometers to 1 micron. In a most
preferred embodiment of the present invention, the width is
approximately 500 nanometers. According to another aspect of the
present invention, the first fluid, which is curable, is a UV epoxy
material which is cured by a UV curing mechanism while the second
fluid is water.
According to an alternate embodiment of the present invention, the
channel of a desired volume to be created is an open microchannel.
In one aspect of the present invention, the method further
comprises a mask during the curing process to provide the
alternating pattern of the cured material. In one preferred aspect
of the invention, the width is in the range of 1 micron to 50
microns. In a more preferred embodiment of the present invention,
the width is in the range of 5 microns to 20 microns. In a most
preferred embodiment of the present invention, the width is
approximately 10 microns. In a preferred embodiment, SU-8 is used
to create the cured walls of the microchannels.
All references, including publications, patent applications,
patents, cited herein are hereby incorporated by reference to the
same extent as if each reference were individually and specifically
indicated to be incorporated by reference and were set forth in its
entirety herein.
EXAMPLE
Example
Constructing a Microchannel of a Desired Volume
An experiment was performed to construct multiple micro channels
within an open channel in a substrate. The steps outlined in FIG. 6
were performed to created the open microchannel of a desired
volume. An open microchannel (602) in a substrate (101) as shown in
FIG. 7a was provided. The open channel microchannel (602) was
filled with a photo resist material, Microchem 660 by using a spin
coating process (1000 rpm, 30 seconds) and baked at 60 degrees
Celsius for 1 hour as illustrated in FIG. 7b. A mask was placed
over the material and the material was exposed to UV light (240
mJ/cm.sup.2) as shown in FIG. 7c. The photo resist material was
developed with 0.26 N Tetramethylammonium Hydroxide (TMAH) for 60
seconds (607) and the uncured material was removed (608). Multiple
open microchannels of a desired volume (610) were created (609) as
shown in FIG. 8.
III. Conclusion
It is to be understood that the above description is intended to be
illustrative and not restrictive. Many variations of the invention
will be apparent to those of skill in the art upon reviewing the
above description and figures. All cited references, including
patent and non-patent literature, are incorporated by reference
herein in their entireties for all purposes.
* * * * *